A special case of copper(II) complex having monodentate and uncoordinated 4-aminopyridine molecules stabilized by highly cooperative supramolecular interactions

A novel mononuclear copper(II) complex, having three monodentate and one uncoordinated 4-ampy molecules and formulated as [Cu(bpy)(4-ampy)3]2·(ClO4)4(4-ampy)2(H2O) (1) (bpy = 2,2′-bipyridine, 4-ampy = 4-aminopyridine), is extended into a one-dimensional (1D) supramolecular chain, where highly self-complementary sandwiched π–π stacking between two bpy ligands and one uncoordinated 4-ampy molecule in the middle and 8-membered N2O2H4 hydrogen-bonding rings between two perchlorate anions and two monodentate 4-ampy molecules of adjacent copper(II) cations are alternately arranged. Here, 1 is a special copper(II) complex having monodentate and uncoordinated 4-aminopyridine molecules simultaneously, which is stabilized by highly cooperative supramolecular interactions. Additionally, two other mononuclear CuII/4-ampy complexes formulated as [Cu(phen)2(4-ampy)]·(ClO4)2 (2) and [Cu(phen)3][Cu(phen)2(4-ampy)]2·(ClO4)6 (3) (phen = 1,10-phenanthroline) have been included.

Graphical abstractA novel mononuclear copper(II) complex 1 having three monodentate 4-ampy and one uncoordinated 4-ampy molecules is extended into a one-dimensional supramolecular chain, where highly self-complementary sandwiched π–π stacking and 8-membered N2O2H4 hydrogen bonding rings are alternately arranged.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Three mononuclear CuII/4-ampy complexes 1-3 have been prepared and fully characterized. ► 1 has an unusual structure where three monodentate and one uncoordinated 4-ampy molecules are present. ► Sandwiched π-stacking spaced by a free 4-ampy and 8-membered H-bonding rings are alternately arranged.